Via Reuters

A General Motors Co engineer who oversaw an internal investigation of the defective ignition switch linked to at least 13 deaths retired on Monday.

Jim Federico, 56, is a previous direct report to now-Chief Executive Mary Barra. He had been executive director of global vehicle integration since September 2013, the No. 1 U.S. automaker said. Before that he was executive chief engineer for global subcompact cars and SUVs, and electric vehicles, and he had worked at GM for almost 36 years.

According to GM documents made public last month by Congress, Federico had received reports from an engineer in the company's product investigations department trying to learn the root cause of air bag failures in GM vehicles. That eventually led to the defective ignition switch. In 2012, Federico had been a "champion" of that probe, a term used to identify a senior executive who marshals internal resources.

GM spokesman Jim Cain said Federico's retirement was his choice and had nothing to do with the switch recall. "We congratulate him on his retirement and wish him the very best in his future endeavors," Cain said.

In an internal announcement of the retirement, GM said Federico planned to "take on new engineering and design challenges outside of the auto industry." Federico could not immediately be reached to comment.

Federico's departure follows the announcement last month that global engineering chief John Calabrese, 55, would retire and his job would be split in two to improve vehicle safety. Company documents provided to congressional investigators show Calabrese was appraised at least once of major developments of the internal probe, but his role in the process is not clear and GM has declined to comment. GM has said Calabrese would remain through August to help with the transition.

Under Federico's direction, the investigative team analyzed ignition switches from GM models at a junkyard and asked the switch supplier, Delphi Automotive, for help.

It was through this process in October 2013 that the team discovered the switch design had been changed years earlier under orders from lead switch engineer Ray DeGiorgio, who was recently suspended by GM. DeGiorgio authorized the design change but did not change the part number, according to documents. That led to confusion as investigators tried to understand why some model years had issues that others did not.

In late January GM began a recall that has grown to include 2.6 million cars globally.